Increased formation of 5-fluoro-2'-deoxyuridine 5'-monophosphate from 5-fluorouracil in the presence of 2-deoxy-alpha-D-ribose 1-phosphate and 2'-deoxyuridine in Ehrlich ascites tumor cells.

In expectation of the elevated formation of an antineoplastic metabolite from 5-fluorouracil (5FU), we examined the additive effect of 2-deoxy-alpha-D-ribose 1-phosphate (dRib1P) and/or 2'-deoxyuridine (dUrd) upon the formation of 5-fluoro-2'-deoxyuridine (5FdUrd) or proximately more antineoplastic 5-fluoro-2'-deoxyuridine 5'-monophosphate (5FdUMP) from 5FU using a crude extract and the whole cells of Ehrlich tumor cells. The amounts of 5FdUrd formed from 5FU by a crude extract were increased in the presence of dRib1P and dUrd, although it was stimulated much more by dRib1P than by dUrd. In the intact cells, the conversion of 5FU to 5FdUMP was also increased by dRib1P, while the presence both of dRib1P and dUrd enhanced the formation of 5FdUrd rather than that of 5FdUMP. These results suggest that the coadministration of 5FU with dRib1P may increase the chemotherapeutic effect of 5FU.